1. Technical Field
The invention relates to a coupling of two similar coupling members for detachably connecting the ends of air brake hoses for trucks or railroad cars to form an airtight connection. More particularly, the invention relates to an improved air brake hose coupling member having locking means preventing accidental rotational separation of a joined coupling.
2. Background Information
Railroad cars and certain types of trucks having pneumatic brake systems use flexible air hoses which extend between separate railroad cars or portions of a tractor-trailer assembly for operation of the pneumatic brake system. A coupling member is attached to each end of the flexible hoses for detachably connecting the hose sections together when individual railroad cars are joined to form a unit train. These couplings are designed and manufactured to meet the requirements of the Association of American Railroads or the Society of Automotive Engineers and are generally similar, so as to be compatible and interchangeable with those of other manufacturers.
These couplings are located between coupled railroad cars for joining together sections of air hose which extend from the braking system of each car. When coupled, the air pressure in the hose lines maintains the brakes of the individual cars in an "off" position. Thus, accidental separation of the coupling between two sections of air hose will apply the emergency car brakes, resulting in sudden stopping of a train with the subsequent delay, inconvenience and expense and chance of accidents.
The couplings on many types of railroad cars are suspended between the cars and hang a short distance above the ground or railroad tracks, four inches minimum, especially when the connecting hoses become worn and have less rigidity, permitting greater sag in the coupling. These couplings are joined together by a rotational downward motion which interengages mating flanges and lugs extending from the coupling members. Occasionally these members become uncoupled prematurely when struck by a raised object or the like lying between the railroad tracks which moves the coupled members upwardly, thus rotating the members in the uncoupling direction. This results in the undesirable emergency stopping of the train.
Several types of locking devices have been devised for known coupling members to prevent such premature uncoupling, such as shown in U.S. Pat. Nos. 3,892,431 and 3,879,066. Although these types of locking devices do reduce the accidental uncoupling of the coupling members, they still will permit premature rotational separation if a sufficient rotational torque is applied thereto, especially when the sealing gaskets become old and worn. Both of these known types of locking devices rely upon the outward pressure exerted on the two coupling members by the compressed gaskets located therebetween to assist in maintaining the members coupled together.
Thus, a need has existed for an improved air brake hose coupling member which enables rapid connection of hose sections in the heretofore usual manner without additional manipulations being required, which does not affect the usual axial separation and operation of such coupling members, and which prevents or considerably reduces premature uncoupling of the attached members.